The U.S. aircraft register, updated daily
Approved modifications · supplemental type certificate · current · amended

SA196SO

Installation of Wright Military Cyclone R-2600-35 engines (as modified per STC SE610SO or R-2600-35 engines having WAD P/N 417916 or 424010 gear boxes). Held by Charlotte Aircraft Corporation, which holds 4 approved modifications in all. Last revised March 20, 1974. System: engine.

What it applies to

Kind of product
Aircraft
Design holder
McDonnell Douglas Corporation; McDonnell Douglas Corporation
Models
DC-4, C54-DC Series
Type certificates
A-762, A-762
On this site
Douglas C-54 7 registered
The FAA's record
On the FAA's site

What an approved modification is

A supplemental type certificate is the FAA's approval of a change to a certified design: a new engine or propeller, avionics, an autopilot, floats, a parachute, a larger fuel tank, an ice-protection kit. The company holding it may sell the kit and the paperwork to owners of the listed models; the modification then becomes part of that aircraft's record. The FAA's list says what was approved and for which models, not how many aircraft carry it.

Source: FAA supplemental type certificates (Dynamic Regulatory System). Register counts from the FAA register of October 20, 2026.